The prior art contains many processes for desulfurizing carbonaceous materials such as coal, cokes, coal products, liquid crudes, and similar materials. These carbonaceous materials contain both inorganic bound and organic bound sulfur. One problem with many of these processes is that they are only capable of removing inorganic bound sulfur and are not very effective in removing organic bound sulfur.
Currently known processes which remove both inorganic and organic bound sulfur have various disadvantages. One problem is that these processes require multiple steps resulting in high operation cost. A second problem is that many of these processes rely on physical separation methods such as magnetic separation, flotation, and the like for removing inorganic bound sulfur. Physical separation techniques are inefficient and also result in higher operation cost.
Processes employing thermal and/or chemical means for removing inorganic bound sulfur also suffer from disadvantages. For example, these processes lower the heating value of the feedstock during sulfur removal. In addition, many of these processes are limited to particular feedstocks as they require the presence of pyrite or marcasite which is then converted to troilite which catalyzes the removal of organic bound sulfur.
In addition, desulfurization processes employing reactive gases such as carbon monoxide, oxygen, nitric oxide, and low carbon alcohols have also been disclosed. These methods however focus upon the desulfurization of only one particular variety of sulfur.
It is therefore an object of the present invention to provide an economical and effective process for desulfurizing carbonaceous materials containing either inorganic bound sulfur, organic bound sulfur, or both. It is a further object of the present invention to provide a process for desulfurizing carbonaceous materials containing both inorganic bound sulfur and organic bound sulfur in a single step. It is still a further object of the present invention to provide a process for desulfurizing carbonaceous materials without substantially depleting the heating value of the original feedstock. Desulfurization processes having these advantages will be readily recognized as an advance in the art and will meet with substantial commercial success.